The major thrusts of the grant will be where the therapeutic efficacy of antibody in combination with various effector cells will continue to receive major attention. In particular the effectiveness of this therapeutic mode will be tested on systemic tumors. Means to improve the delivery of antibody to various tumor sites to enhance the availability of effector cells within the tumor bed and attempts at defining and eliminating various inhibitory barriers (ie. suppressor cells) will all be studied. The role of viruses as etiological agents and diagnostic tools, potential targets of immune attack or immune response modifiers will also receive major attention. Studies on the potential use of retroviruses as vectors to specifically target tumors of certain tissue derivation will be continued with molecular approaches included in order to define the genetic elements responsible for tissue tropism. Further investigation of the secretory immune system in relation to epithelial malignancies will be carried out. Attempts to correlate elevated levels of SIgA with the degree of displasia in sputum and bronchial secretions will be undertaken.